Series and Parallel Resistance New

7/31/2019 Series and Parallel Resistance New

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Resistance in Series and

Parallel


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What is Circuit?

What is Electric Circuit?

Resistance in Series

Voltage division technique Resistance in Parallel

Current division technique

Comparison Application


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What is Circuit?

The word "circuit" comes from the Latin word for

circle

A circuit is a closed path followed by an electric

current


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What is Electric Circuit?

A basic electric circuit is an arrangement of physicalcomponents which utilize voltage, current, andresistance to perform some useful function.

Type of arrangement of physical components:

Series circuit

Parallel circuit

Series and Parallel (combinational) circuit


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The circuit in which resistance are connected end to

end so that there is one path to the current flow is

called series circuit.


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Current is constant

Why? Only one path for the

current to take

V I R


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In terms of conductance

1/GT = 1/G1 + 1/G2 + 1/G3


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Total resistance in a series circuit is the sum ofall the resistor values

Power in series resistanceI2RT= I

2 R1 + I2R2

Total power in series circuit is the sum of powerconsumed by individual resistance


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Voltage Division Technique

The equivalent resistance of any number of resistors

connected in a series is the sum of the individual resistances

By ohms Law

I=V/RT

V1=IR1, V2=IR2,..Vn=IRn

V1=(V/RT) R1,

Voltage across any resistance in the series circuit,

=V (Rx / RT)

N

n

nNeq RRRRR1

21


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Resistance in Parallel

Parallel: Two or more elements are in parallel if theyare connected to the same two nodes andconsequently have the same voltage across them.


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V I R

1 2 3

1 2 3 1 23

23 2 3

1 2 3

where

1 1 1 1

V V V V

I I I I I II I I

R R R R

Voltage is constant There are 3 closedloops in

the circuit


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231 2 3 2 3 1 23

123 1 2 3

123 1 23

1 2 3

1 2 3

1 2 3 1 2 3

1 1 1 1 1 1 1 1 1 1

1 1 1 1

1

1 1 1 1 1 1

let so

and

R R R R R R R R R R

R R I I I I

R R R R

I I IV I R I I I

R R R R R R


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TotalParallel Resistance: RT

The inverse of the total resistance of the circuit (also

called effective resistance) is equal to the sum of the

inverses of the individual resistances.


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Totalconductance: GT

For parallel elements, the total conductance is the

sum of the individual conductance values

Power in Parallel resistance

V2/ RT= V2 / R1 + V

2 / R2 + V2/ R3

The total power consumed in a parallel circuit is equal to thesum of power consumed by individual resistance.

NTGGGGG ...

321


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Voltage Across Parallel Element

The voltage across parallel element is the

same.

V=10v

R1

20k

R2

30k

R3

60k

V=10v

Vs

10Vdc

V=10v


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Comparison of Series and Parallel Series Circuit

Current is same

Voltage across all elements

depends on resistance

Voltage drops, resistances

and Powers are additive

Applied Voltage = sum of

different voltage drops

Parallel Circuit

Voltage is same

Current in all elements

depends on resistance

Total resistance is always

less than the smallest ofresistance

Powers, conductance and

branch currents are

additive in nature If N equal resistance are

connected in parallel then


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Comparison of Series and Parallel

Disadvantage of Series

Connection

Break in one point

affects the entire circuit Not practicable for

lighting circuits

Devices with different

current rating cannot beconnected in series

Advantage of parallel

connection

Appliances rated for

same voltage butdifferent power can be

connected in parallel

Break in any one branch

does not affects other


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Applications of Parallel Circuit

Toll Way

Car Electric Diagram

LEDs Home Wiring design
http://localhost/var/www/apps/conversion/releases/20121024195125/tmp/scratch_4/applications.htmhttp://localhost/var/www/apps/conversion/releases/20121024195125/tmp/scratch_4/applications.htm


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THANK YOU

Series and Parallel Resistance New

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